What is Liquid Rubber Seam Tape used for? Liquid Rubber Seam Tape is used for sealing gaps, cracks, joints, tears, flashings, skylights, gutters.... Related articles Do I have to coat Liquid Rubber Seam Tape? How should I prepare the surface? What product do you recommend for a 20x20 flat roof ( pitched 4 1/2" over 20' ) which will be planted. AKA green roof? How does it seal? Phone Number Comments 0 comments Article is closed for comments.